Entity Framework Core 多对多更改导航属性名称

Question

I have a table called "LogBookSystemUsers" and I want to setup many to many functionality in EF Core 5. I almost have it working but the problem is my ID columns are named SystemUserId and LogBookId but when EF does the join it tries to use SystemUserID and LogBookID . This is my current configuration code:

modelBuilder.Entity<SystemUser>()
            .HasMany(x => x.LogBooks)
            .WithMany(x => x.SystemUsers)
            .UsingEntity(x =>
            {
                x.ToTable("LogBookSystemUsers", "LogBooks");
            });

I tried this:

modelBuilder.Entity<SystemUser>()
            .HasMany(x => x.LogBooks)
            .WithMany(x => x.SystemUsers)
            .UsingEntity<Dictionary<string, object>>("LogBookSystemUsers",
                x => x.HasOne<LogBook>().WithMany().HasForeignKey("LogBookId"),
                x => x.HasOne<SystemUser>().WithMany().HasForeignKey("SystemUserId"),
                x => x.ToTable("LogBookSystemUsers", "LogBooks"));

But that just adds two new columns instead of setting the names of the current columns.

This is all database first. I don't want to have to use a class for the many to many table because I do this all over in my project and I don't want a bunch of useless classes floating around. Any ideas?

Answer 1

Interesting bug, consider posting it to EF Core GitHub issue tracker.

By idea what you have tried should do it

modelBuilder.Entity<SystemUser>()
    .HasMany(x => x.LogBooks)
    .WithMany(x => x.SystemUsers)
    .UsingEntity<Dictionary<string, object>>("LogBookSystemUsers",
        x => x.HasOne<LogBook>().WithMany().HasForeignKey("LogBookId"),
        x => x.HasOne<SystemUser>().WithMany().HasForeignKey("SystemUserId"),
        x => x.ToTable("LogBookSystemUsers", "LogBooks"));

And it works for any other FK property names except the {RelatedEntity}Id when related entity PK property is called ID .

As workaround until it gets fixed, define explicitly the desired join entity properties before configuring the relationship:

// add this
modelBuilder.SharedTypeEntity<Dictionary<string, object>>("LogBookSystemUsers", builder =>

{
    builder.Property<int>("LogBookId");
    builder.Property<int>("SystemUserId");
});
// same as the original
modelBuilder.Entity<SystemUser>()
    .HasMany(x => x.LogBooks)
    .WithMany(x => x.SystemUsers)
    .UsingEntity<Dictionary<string, object>>("LogBookSystemUsers",
        x => x.HasOne<LogBook>().WithMany().HasForeignKey("LogBookId"),
        x => x.HasOne<SystemUser>().WithMany().HasForeignKey("SystemUserId"),
        x => x.ToTable("LogBookSystemUsers", "LogBooks"));